Percutaneous coronary interventions (PCI) involving balloon angioplasty and stenting are effective in the treatment of acute coronary syndromes (ACS) including myocardial infarction (MI), but reduced coronary flow and distal embolization frequently complicate interventions when thrombus is present. Moreover, PCI in thrombus-containing lesions represents a clinical challenge to the interventionalist since thrombus is a predictor of adverse outcomes.^1,2 Distal embolization of thrombus, fibrin content and other atherosclerotic particulate matter can lead to a varying degree of consequences ranging from asymptomatic cardiac enzyme leak to flow-limiting microvascular obstruction, which may result in no reflow, abrupt occlusion, periprocedural MI, emergent coronary artery bypass graft (CABG) surgery and death.

Percutaneous coronary intervention (PCI) for acute myocardial infarction (MI) in the setting of angiographic thrombus is associated with an increased risk of reocclusion and recurrent infarction.1,2 Distal embolization of thrombus during PCI is thought to be a major contributor to impaired tissue level perfusion. Previous studies have shown the efficacy of AngioJet Rheolytic Thrombectomy (Possis Medical, Minneapolis, Minnesota) in reducing thrombus burden and improving coronary flow.3,4 However, no study to date has specifically evaluated the use of AngioJet Rheolytic Thrombectomy (RT) in patients undergoing rescue PCI for failed thrombolytics. Given the high thrombus burden in this setting, AngioJet RT would be expected to be particularly useful and associated with marked improvements in thrombus burden and coronary flow.

Percutaneous coronary intervention (PCI) for acute myocardial infarction (MI) in the setting of angiographic thrombus is associated with an increased risk of reocclusion and recurrent infarction.^1,2 Distal embolization of thrombus during PCI is thought to be a major contributor to impaired tissue level perfusion. Previous studies have shown the efficacy of AngioJet Rheolytic Thrombectomy (Possis Medical, Minneapolis, Minnesota) in reducing thrombus burden and improving coronary flow.^3,4 However, no study to date has specifically evaluated the use of AngioJet Rheolytic Thrombectomy (RT) in patients undergoing rescue PCI for failed thrombolytics. Given the high thrombus burden in this setting, AngioJet RT would be expected to be particularly useful and associated with marked improvements in thrombus burden and coronary flow.

In order to explore the use of AngioJet rheolytic thrombectomy in general clinical practice, the database of the Strategic Transcatheter Evaluation of New Therapies (STENT) Registry was used to assess both the utilization and clinical outcomes of patients receiving AngioJet versus patients not receiving thrombectomy for high grades of thrombus. Between May 2003 (initiation of the STENT Registry) and December 2005, 17,582 total percutaneous coronary interventions (PCIs) were entered into the registry. Of these, 10,406 were eligible for 9-month follow-up (patients enrolled through February 2005) and of these, 9-month clinical follow-up was obtained in 9707 (93% follow-up rate). These data are derived from nine interventional cardiology centers primarily located in the Southeast and Midwestern areas of the United States.

Primary percutaneous coronary intervention (PCI) helps to achieve brisk coronary flow (thrombolysis in myocardial infarction [TIMI] 3 flow) in the infarct artery in greater than 90% of patients with ST-elevation myocardial infarction (STEMI) and has achieved excellent outcomes with very low rates of death, re-infarction and stroke.¹ As a consequence, primary PCI has become the preferred reperfusion strategy for STEMI. Despite this, primary PCI is limited by suboptimal myocardial reperfusion (microvascular reperfusion) in many patients as well as limited myocardial salvage. Intracoronary thrombus is thought to be ubiquitous in the infarct artery of patients with STEMI. When visible thrombus embolizes to the distal circulation during primary PCI, outcomes are compromised.

Against an atherosclerotic background of progressive accumulation of mural lipid, the episodic acute exacerbations of coronary artery disease (acute myocardial infarction [MI] and unstable angina) invariably involve the deposition of platelet-fibrin (white) thrombus, as well as classic (red) and mixed thrombus. The therapeutic approach to stabilizing such acute syndromes may be as simple as initiating effective anti-platelet therapy (aspirin, clopidogrel and platelet glycoprotein IIb/IIIa receptor blocker) or the addition of an anti-thrombin (heparin or low molecular weight heparin), before sending the patient for diagnostic angiography and stent implantation to treat the underlying atherosclerotic obstruction(s).

Macro- and microembolization during percutaneous coronary intervention (PCI) is frequent and may result in the obstruction of the microvessel coronary network.¹ In the setting of acute myocardial infarction (AMI), PCI-related embolization results in a decreased efficacy of mechanical reperfusion and myocardial salvage. Direct stenting without predilation may decrease embolization and the incidence of the no-reflow phenomenon.^2,3 More specific approaches to the problem of microvessel embolization during PCI include thrombectomy by different techniques, and the use of anti-embolic protection devices.

This symposium has sought to understand and resolve some of the disparate results from studies evaluating thrombectomy with primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) and has attempted to provide a rational approach for current management of patients treated with primary PCI who have large thrombus burden. Most of the randomized trials evaluating adjunctive thrombectomy with primary PCI have enrolled small numbers of patients, and all of the trials have used surrogate endpoints — usually measures of myocardial reperfusion (such as ST-segment resolution and angiographic myocardial blush) or infarct size. Four randomized trials with aspiration thrombectomy have yielded conflicting results — three showing improved myocardial reperfusion with thrombectomy and one showing larger infarct size with thrombectomy.